The invention relates to a connector for accurately connecting the ends of optical fibre lines used to transmit light energy from a light source such as a semiconductor laser to a light receiver such as a photodiode.
As is known in the art the transmission of light energy by means of optical fibre lines has certain advantages. Thus the optical fibre line provides:
1. A remarkably high capacity of information transmission per unit section area. PA1 2. A low damping factor. PA1 3. Ease of installation and high flexibility in use. PA1 4. Non inductive interruption because of the use of an electric insulating material.
Because of these advantages attempts are being made to use the fibre optics transmission line in fields such as long-distance large capacity communications, data transfer in computer systems, circuits used in aircraft, CATV circuits, and others.
However heretofor an effective transmission line to be used for optical communication has not been realized, because of the fact that these have not yet been developed a satisfactory connector capable of connecting the adjacent ends of optical fibres in alignment.
In the union between the adjacent ends of the optical fibres, it is required that a core and a clad of the end of one side be precisely and completely united with the corresponding parts of other side. In case this union slips and becomes imperfect, communication will become impossible as a result of light leakage. Consequently a precision degree in perfect union of the connection is required in the use of a single mode fibre and multi mode fibre where the boundary between core and clad is clear and in the use of a focusing type fibre such as selfoc which is so constructed as to decrease little by little the refractive index towards the clad from the core in the selfoc. It is also desirable that a connector for uniting the cores of two fibre ends, which are fine or hair-like threads, should be developed.
Therefore it is a first object of the present invention, considering above mentioned needs, to provide a low cost and easily operated connector which will unite precisely and perfectly adjacent ends of optical fibre ends and which will retain them in a satisfactory united condition.
Further, the length of the optical communication fibres now on the market have been generally standardized at one kilometer long. This presents somewhat of a problem when it is necessary to confirm the degree of unions between adjacent ends of the fibres. Thus in attempting to confirm whether there is any optical leakage at the union it is necessary to detect this from the end of the fibre opposite the union or from 1 kilometer away. Accordingly, this operation becomes a very large scale project. Therefore, it is desirable that any optical leakage should be easily and rapidly detected at the connector and should be corrected there. Consequently the complete union should be confirmed by detecting the point where the optical leakage becomes zero. However, as is known, the circumference of the optical fibre is covered over with cladding glass which is of a low refractive index, so it is not considered appropriate to detect an abnormal damping resulting from said optical leakage if it is necessary to peel off the cladding glass.
The second object of the present invention, considering the above mentioned needs, is to provide an optical fibre end connector which not only permits a complete connecting operation to be quickly made but also providing at the connector itself means whereby optical leakage can be detected.
Furthermore, as the optical fibres are of very small diameter, the connector holding the end of the optical fibres must also be manufactured in super small sizes. It follows that if slight errors in manufacturing the connectors occur there may be problems involved in installing them. Therefore, it is desirable that such connectors be capable of being finely adjusted in a direction both toward the longitudinal center line of the connector and the circumference thereof to compensate for any deficiencies in manufacture.
The third object of the present invention, considering the above mentioned needs, is to provide an optical fibre end connector capable of being adjusted through a wide range and particularly adjustments toward and through the longitudinal center line of the connector.
The fourth object of the present invention is to provide an optical fibre end connector which enables one to magnify and actualize the range wherein adjustment is possible in uniting ends of the fibre, towards the circumference.